1. Field of the Invention
The invention relates to a method of revising edges of an images in a liquid crystal display (LCD) device, and more particularly, to a method of revising edges of an images of an LCD device being capable of removing a noise in an image and resolving a blurring problem in edges of an image.
2. Discussion of the Related Art
The related art LCD device includes a liquid crystal panel and a backlight unit providing light onto the liquid crystal pixels. The liquid crystal panel includes a plurality of liquid crystal pixels arranged in a matrix shape and a thin film transistor (TFT) on a substrate. The TFT controls a supply of image data for adjusting a light transmittance through the liquid crystal pixels by controlling a rotation angle of liquid crystal molecules in the liquid crystal pixel. The LCD device displays a desired gray level by transmitting the light through the liquid crystal panel.
A noise in a digital image is removed to obtain a high quality displaying image. For example, the noise includes a white noise or an impulse noise. The noise is added on digital data when images are generated by the LCD device.
The noise is simply removed by using a low-pass filter (LPF). The noise is almost removed by the LPF. However, there is a blurring problem in edges of an image when the LPF is used.
The LPF for removing the noise in the image, for example, has a filter having a fixed 5*5 pixel size. Since a color information of a high frequency part is distorted in a part having a sudden image change, edges of the image is blurred.
Accordingly, not only removing the noise but also conservation of edges of image is required. To meet these requirements, a method of “Speckle Filtering of SAR Images Based on Adaptive Windowing” is introduced by a first issue of an eleventh volume (pages 719-722) of a collection of learned papers published by “The Institute of Electronics Engineers of Korea” on 1998.
In the Adaptive Windowing method, an image is classified into a homogeneous area, where there is scarcely an image change, and a heterogeneous area, where there are much image change through analyzing the image. A noise filtering process is performed with a filter having a large size in the homogeneous area. For example, the filter having a 9*9 image window size is enlarged into an 11*11 or 13*13 window size. On the other hand, a noise filtering process is performed with a filter having a smaller size in the heterogeneous area to remove a noise in the image and prevent a blurring problem in edges of the image. For example, the filter having a 9*9 image window size is reduced into a 7*7 or 5*5 window size.
Unfortunately, even if the image is filtered with a noise filter having the minimized window size by the Adaptive Windowing method, there is still a blurring problem in the heterogeneous area.